This was the first time an FA Cup tie had ever been played in a Saturday evening prime-time slot and what transpired was "box office," thanks to a thrilling game that West Brom won and which was dominated by usage of the video assistant referee (VAR).

On frequent occasions at Anfield, both sets of supporters did not appear to know what was going on because of the confusion VAR has created. The unfortunate man with the earpiece was referee Craig Pawson, who was in contact with the TV screen-viewing Andre Marriner.

As if the drama of the opening 11 minutes was not enough, during which time Liverpool went ahead through Roberto Firmino before Jay Rodriguez scored twice for West Brom, what followed soon afterward was a succession of technology-influenced events.

VAR first reared its controversial head, in the 19th minute, West Brom thought they had taken a 3-1 lead as Craig Dawson headed in off a corner. But as he and his teammates wheeled away in celebration, Simon Mignolet pleaded to Pawson that he had been obstructed by an offside Gareth Barry. After a delay that had Anfield in near-silence awaiting the decision, the goal was chalked off.

Four minutes later, half-hearted Liverpool appeals for a penalty when Jake Livermore pulled back Salah were ignored by the match officials. But then Pawson, having consulted with Marriner, went over to the touchline to view replays before coming to the conclusion that Salah had, in fact, been fouled.

The incident occurred in the 23rd minute, but it was not until the 27th that Firmino struck his spot kick. The Brazilian forward's effort hit the underside of the bar and bounced out to safety, whereupon dissenting West Brom fans, feeling they had been hard done by twice, chanted "F--- VAR."

And during four minutes of added time at the end of an action-packed first half, there was time for another goal and replay incident. Dawson's mishit shot deflected off Joel Matip into the net, and after check for offside, the goal stood and West Brom went into the break 3-1 in front.

VAR was used again in the second half when Dawson clearly netted from an offside position, and the feeling grew that the fledgling system creates confusion every time it is used and therefore disrupts the flow of the game. The FA has work to do in order to make VAR a permanent, accepted fixture.

Referee Craig Pawson was the centre of attention at Anfield on Saturday. Getty

2. Another trophy chance slips away from Liverpool

The FA Cup represented Liverpool's best chance of improving a record that has seen the club win just one trophy since 2006, but the opportunity has slipped by. With just the Champions League and Premier League left to play for, there is a good chance that Jurgen Klopp's wait for a first Anfield honour will stretch into 2018-19.

Despite injuries and an unstable position in the top four, Klopp's lack of changes to his lineups in the competition show how seriously he had been taking it, but while VAR will get the headlines after this game, it will take some of the spotlight off a discouraging Liverpool performance for the second consecutive game.

Typically under Klopp, Liverpool have come out firing after a defeat; the 4-1 drubbing at Tottenham Hotspur in October, for example, kick-started the 18-game unbeaten run that ended at Swansea on Monday. But this disjointed performance, with many players who are likely to feature at Huddersfield on Tuesday, does not inspire too much hope that a turnaround is forthcoming.

Finishing fourth may be seen as a trophy in the eyes of football club board members, but players themselves actively seek to lift trophies and wear medals around their necks. Mohamed Salah's strike in the 77th minute made it 3-2 and kept those faint hopes alive until the final whistle, but Liverpool could find no more inspiration.

3. West Brom enjoy cup boost

2018 might be the 50th anniversary of West Brom's last FA Cup triumph, but manager Alan Pardew had admitted Saturday's tie at Anfield was less of a priority than Wednesday's night League visit to Manchester City.

Despite improved performances and a more pleasing style of play in recent times, West Brom remain in the relegation zone and Pardew, who was appointed in November, has just one league win since taking charge.

But managers have to live in the present, and West Brom were rewarded for making a good go of things from the start at Anfield. They knew where to target Liverpool, pressing defensive frailties to devastating effect.

Meanwhile, the movement of forwards Rodriguez and Hal Robson-Kanu had Liverpool's holding midfielder Emre Can and centre-halves Matip and Virgil van Dijk scrambling for the opening two goals.

A cup run may well hamper West Brom's attempts to stave off relegation by putting extra strain on his squad -- Robson-Kanu and Kieran Gibbs both limped off with apparent injuries at Anfield -- but on the flip side, it could also generate the momentum that Pardew needs.